Refrigerating coil



Marh 29, 1949. F. J. HIBBS REFRIGERATING COIL 5 Sheets-Sheet 1 Filed May 11, 1945 March 29, 1949. F. J. HIBBS 2,465,873

REFRIGERATING COIL v Filed May 11, 1945 5 Sheets-Sheet 2 gwu c wton .EoTHbbbs March 29, 1949. F. J. HIBBS REFRIGERATING COIL 5 Sheets-Sheet 5 Filed May 11, 1945.

awe/Wm 5 Sheets-Sheet 4 F. J. HIBBS REFRIGERATING COIL $m n MN W March 29, 1949.

Filed May 11, 1945 March 29, 1949. F. J. HIBBS 2,465,873

REFRIGERATING COIL Filed May 11, 1945 5 Sheets-Sheet 5 INYENTOR.

Patented Mar. 29, 1949 REFRIGERATING COIL Frank J. Hibbs, Los Angeles, Calif., assignor to Associated Refrigerating Engineers, Los Angeles, Calif., a corporation of California Application May 11, 1945, Serial No. 593,239

8 Claims. 1

This invention has special reference to coils of the type which are used in refrigerating plants and the like.

One important object of the invention is to provide an improved general arrangement of coils for this purpose.

A second important object of the invention is to provide an arrangement of pipes in such reirigerating devices which will provide a large evaporative area for the refrigerating liquid with relatively short lengths of piping assembly.

A third important object of the invention is to provide a refrigerating device wherein one or a series of individual pipe lengths serve to each receive refrigerating liquid and each to constitute an evaporating unit, the liquid entering and the gases of evaporation leaving from a common end.

A fourth object is to provide means whereby the said common end of a pipe is of relatively large area, which may be due to inclination of the pipe, so that there will be minimum restriction to-the flow of gas and the latter may flow unhampered by the liquid present.

A fifth object is to provide a refrigerating device with one or a multiple of outlets from which the gases due to evaporation can freely escape, thus causing a minimum of restriction by the evaporating liquid to the free flow of the generated gas leaving the refrigerating coils.

A sixth object is to provide a generally horizontal header having a return pipe rising into the same and an inclined pipe extending laterally from the header, so that liquid will be retained in the header and pipe to the level of the return pipe.

A seventh object is to provide a refrigerating coil, in which it is possible, to quickly remove the accumulated snow or frost from the outer surface of the coil (commonly known as defrosting) by so valving the coil as to permit it to be changed temporarily from an evaporating coil to a condensing coil. Since the coils readily permit the flow of gas outward, when used for evaporation, by the same token they permit when providing gas at higher pressure, the flow of the gas inward when used as a condenser, the heat of condensation freeing the frost quickly and efficiently from the entire coil surface which is everywhere immediately accessible to the incoming gas.

An eighth object of the invention is to provide a pair or series of pairs of pipes arranged in accordance with the third object but having a common end closure for each pair.

A ninth important object of the invention is to provide novel arrangements of headers and evaporating units connected thereto.

A further object is to provide an arrangement in which the spacing of the various pipes making up the unit is not limited to dimension required by return bends, but may be spaced at will both vertically and horizontally.

With the above and other objects in view, the invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings and particularly claimed.

In the accompanying drawings, wherein like characters of reference indicate like parts in the several views,

Figure 1 is a side elevation of a refrigerating device constructed in accordance with this invention;

Figure 2 is a fragmentary section on the line 2-2 of Figure 1;

Figure 3 is a fragmentary section on the line 3-3 of Figure 2;

Figure 4 is a view similar to Figure 3 but showing a modification of the evaporating units used herein;

Figure 5 is an enlarged sectional view showing one arrangement of the pipes constituting the evaporating units;

Figure 6 is a view similar to Figure 5 but showing the second arrangement of such evaporating units;

Figure 7 is a detail sectional view illustrating a modification of overflow arrangement for the evaporating units;

Figure 8 is a view substantially like Fig. 7 of a further modified form, and

Figure 9 is a view primarily in side elevation of a form which uses a single header.

In the arrangement herein disclosed, I have dealt by way of example, primarily with a type of refrigerating device which may be employed at the side of a room, or be located between the walls of the room by suitable framing. However, from what follows, it will be obvious that a similar arrangement with one or more horizontal banks of evaporating units may be used under the ceiling of a room. Obviously, the specific arrangement of devices of this character must be such as to suit the size and shape of the room and the purpose for which the room is intended. For instance, a room intended for quick freezing must have considerably greater area of evaporating piping than a room merely intended for the preservation of food without 3 freezing or after having been frozen. Since there is such a wide variety of piping arrangements for the various purposes involved, it is to be understood that the piping arrangement here shown is to be taken as an example only and as typical of all such arrangements.

Referring now to Figure 1, an accumulator I9 is fed with refrigerating liquid from a suitable source of supply, such as an ammonia ipump, through a pipe ll, regulated or controlled by a float valve l2 of any preferred construction or if preferred by a hand-operated valve, which valve I2 is connected with the accumulator l through pipes I3 and It disposed so that the liquid level will be maintained substantially at the line 15. The pipes i3 and 14 are provided wtih valves l6 and I1, and a valve I8 is located in the pipe H in advance of a liquid scale trap 19 of any preferred construction. The chamber of float valve I2 is connected by a pipe 28 to a top header 23, and a valve 2| is interposed in the pipe 20. Said float valve l2 causes the liquid to flow through line 20 as aforesaid to replace liquid evaporated in the coil as fast as such evaporation occurs. The accumulator receives any surplus or any liquid boiling over from the coil, such liquid being then'evaporated in the lowest coil 32, which is below the level maintained in accumulator H] by float valve I2. From the upper end of the accumulator It] extends a valved suction pipe 22 which may be connected to the suction side of the pump above-mentioned.

As illustrated in Figures 1 to 6 a series of said horizontal headers 23 are disposed in spaced vertical alinement one above the other and each of these headers is connected by means of a pipe 24 with the accumulator l0. Said pipes 24 are incli'n'ed upwardly from the headers 23 to the accumulator ID in order that no liquid but gas only may flow through them from headers 23 to accumulator Ill. Below this bank of headers is a further header 25 which is connected to the accumulator It by horizontally disposed pipe 26, which permits surplus liquid as well as gas to flow to the accumulator.

Extending from each header is a series of horizontal pipes 21, each constituting an evaporating unit, and being weld-connected to the respective headers and having the remote ends closed as at '28. This arrangement can best be seen by reference to Figure 5. The headers are successively connected from top to bottom by vertical pipes 29 and the upper end of each of the vertical pipes extends upward in the header to lie slightly below the center line thereof as shown at 30. The arrangement of the pipes 29 is such that they are staggered so that liquid flowing down one of the pipes into a header will not directly enter the pipe leading from that header to the next header below.

Again referring to Figure 5, it will be seen that because of the horizontal disposition of the evaporative units 21, these units will never be more than partly filled with liquid refrigerant 3| as indicated by the numeral 33 since any excess of liquid refrigerant will overflow through the respective pipes 29. Liquid entering the top header 23 will fill that header and its connected series of horizontal pipes to the level of the overflow.

When the top header and its series of pipes are filled to this level, the additional liquid overflows to the next header below filling it and its series f con in pipi g. When all the headers have been filled surplus liquid flows through pipe 26 to accumulator l0 raising the liquid level to level i5 and causing the float valve to reduce the flow. Since liquid is continuously evaporating in the coil system and must be rep-laced, float valve 12 does not entirely out off the flow of liquid but reduces it to the amount required to maintain the desired level in the accumulator. While evaporative units connected to the lowest header 25, and the pipes 32, may be level, they are preferably inclined from the header upwardly to a slight extent. If level, pipes 32 are, due to float level line i5 being higher, entirely filled with liquid and all gas generated in these pipes is restricted in flow throughout the entire length of the pipe. If, however, the pipes are inclined upward, then the liquid level in the pipes is established by the inner top periphery of the pipe at its header end and the pipe may be so inclined that the standing level of the liquid is at or near the inner bottom of the pipe at its far end. Thus gas flow is only restricted by liquid for a short distance at the outlet or header end of the pipe. Furthermore, when defrosting, gas can force its way into this area above the liquid to replace gas which has condensed, thus releasing heat for defrosting. This cannotoccur if the pipes are entirely filled with liquid and no space left for gas.

A slightly different arrangement of the evaporative units is shown in Figure 6 wherein the lower unit 32 is arranged as in Figure 5, but the units above are, as indicated at 34, inclined downwardly from the respective headers. This inclination is such that the upper surface at'the closed end of each pipe 34 is in horizontal alinement with the upper end of the respective overflow pipe 29 for the header from which the-pipe 3 3 extends. This arrangement provides fora gas chamber 35 extending from end to end of the unit over the liquid 3! and becoming progressively greater toward the header, and giving a smaller area of liquid contact with the evaporating surface adjacent said header. This restriction in gas area is allowable at the outer end because at that end only the gas produced at the immediate spot must be handled but the header end must handle all the gas produced in the pipe for its entire length.

As shown in Figures 1 to 4, the evaporative units preferably in banks in staggered relation, may be supported on bars 36 of vertical frame members 37. Obviously for supporting evaporative units for ceiling purposes, two horizontal headers may be employed, these headers corresponding to the lowest header 23 and the header of the previously described arrangement.

Instead of using the closures 23 illustrated in Figure 5, I may connect each horizontally'disposed pair of units 38 by a return bend or U-bend 539 as in Figure 4. Obviously the pairs of pipes will be either horizontal as in Figure 5 orinclined as in Figure 6. In either case there will be evaporative surface on the liquid extending from end to end of each pipe In the form of the invention shown in Figure '7, the accumulator it is used, but in this each header it is connected to the accumulator by a horizontal pipe GI which extends into the accumulator, being cut away as at Q2, and is provided with an upwardly extending flange 33 at its-inner end to form a dam against which the liquid3l held in the pipe ill may abut. This dam is higher thanthe upper end of the respective pipe 29'so that there is no danger of the liquid 3! running over the dam.

Again header connection'ill, as in Fig. 8, may have a dam at 43* the area of the'pipe ndjand the outlet i2 may be a hole in the top of pipe 4|; otherwise the same reference characters have been applied as in Fig. 6.

As shown in Fig. 9, a single header, rather than the plurality of headers of Figs. 1 to 4, but without the accumulator, may be used. The same reference characters as in Figs. 1 to 4 apply.

In operation whenever the temperature of the room in which the device of the invention is installed falls below the desired temperature, the pump is started in the usual manner by hand or through the instrumentality of a thermostat. This causes the flow of liquid past the float valve 12 into the headers and thus into the evaporating units. As previously described each of these units presents an open evaporative surface substantially equal in area to the length of the unit multiplied by internal diameter of the unit. Since the transfer of heat from the metal of th pipe to the refrigerant liquid, and the conductivity of the metal in the pipe also, is many times greater than the transfer of heat from the air in the room to the metal of the pipe, no appreciable loss is occasioned by the liquid not being in contact with the entire inner surface of the pipe. There will be no filled pipes except in bottom tier and since this large free evaporative area persists during evaporation of the liquid into gas and the gas has a free outlet unrestricted by the liquid a highly efficient and rapid cooling is thus effected with the corresponding rapid heat at transfer from the room to the refrigerating medium.

What is claimed is:

1. In a refrigerating apparatus, a plurality of horizontal headers spaced vertically one above another, a plurality of series of evaporating pipes each having one end open and the other closed, the pipes of each series having their open ends connected to a respective header, overflow pipes each connecting a header with the next below, a further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upward therefrom, an overflow pipe connecting said last header with the one above, and means to maintain evaporative liquid at a point midway of said last overflow pipe.

2. In a refrigerating apparatus, a plurality of horizontal headers spaced vertically one above another, a plurality of series of evaporating pipes each having one end open and the other closed, the pipes of each series having their open ends connected to a respective header and having their axes slightly inclined downwardly from the open ends to the closed ends, overflow pipes each connecting a header with the next below, a further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upward therefrom, an overflow pipe connecting said last header with the one above, and means to maintain evaporative liquid at a point midway of said last overflow pipe.

3. In a refrigerating apparatus, a plurality of horizontal headers spaced vertically one above another, a plurality of series of evaporating pipes each having one end open and the other closed, the pipes of each series having their open ends connected to a respective header, overflow pipes each connecting a header with the next below, a further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upwardly therefrom, an overflow pipe connecting said last header with the one above, means to maintain evaporative liquid at a point midway of said last overflow pipe, a vertical accumulator, and pipes each connecting a respective header to said accumulator.

4. In a refrigerating apparatus, a plurality of horizontal headers spaced vertically one above another, a plurality of series of evaporating pipes each having one end open and the other closed, the pipes of each series having their open ends connected to a respective header, overflow pipes each connecting a header with the next below, further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upwardly therefrom, an overflow pipe connecting said last header with the one above, means to maintain evaporative liquid at a point midway of said last overflow pipe, a vertical accumulator, and pipes each connecting a respective header to said accumulator, said last pipes inclining upwardly from the headers to the accumulator.

5. In a refrigerating apparatus, a plurality of horizontal headers spaced vertically one above another, a plurality of series of evaporating pipes each having one end open and the other closed, the pipes of each series having their open ends connected to a respective header, overflow pipes each connecting a header with the next below, a further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upwardly therefrom, an overflow pipe connecting said last header with the one above, means to maintain evaporative liquid at a point midway of said last overflow pipe, a vertical accumulator, and pipes each connecting a respective header to said accumulator, said last pipes extending into the header and opening upwardly therein.

6. In a refrigerating apparatus, a plurality of horizontal headers spaced vertically one above anoth r, a plurality of series of evaporating pipes each having one end open and the other closed, the pipes of each series having their open ends connected to a respective header and having their axes slightly inclined downwardly from the open ends to the closed ends, overflow pipes each connecting a header with the next below, a further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upward therefrom, an overflow pipe connecting said last header with the one above, and

means to maintain evaporative liquid at a point midway of said last overflow pipe, a vertical accumulator, and pipes each connecting a respective header to said accumulator.

7. In a refrigerating apparatus, a plurality of horizontal headers spaced vertically one above another, a plurality of series of evaporating pipes each having one end open and the other closed, the pipes of each series having their open ends connected to a respective header and having their axes slightly inclined downwardly from the open ends to the closed ends, overflow pipes each connecting a header with the next below, a further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upward therefrom, an overflow pipe connecting said last header with the one above, means to maintain evaporative liquid at a point midway of said last overflow pipe, a vertical acano e-7a eumulatonsandipipes each connecting arespecti-Ve -lne'ader to said accumulator, said last pipes inclining upwardlyiromxthe headers to the-actcumulator.

8. In a ref-rigcrating: apparatus, a plurality of horizontal headers spaced vertically one above another, a plurality of series of evaporating pipes each having one end open andthe other closed, the pipes of eachseries having their open ends connected to a respective header and having their axes slightly inclined downwardly from the open ends'to the closed ends, overflow pipes each connecting a' header with'the next below, a further header spaced below the lowest header of the plurality of headers, evaporating pipes having open ends connected to the last header and inclined slightly upwardlytherefrom, an overflow pipe connecting said last header with the one above,

file of this patent:

means 't'o-maintain 'evaporative liquid at'a point midway'of said last-overflow pipe, a vertical accumulator, and pipes each connecting a respectiVEhealdQl to said accumulator, said last pipes extending-into the header and opening upwardly therein.

FRANK J. HIBBS.

1 REFERENCES CITED The following references are of record in the UNITED STATES PATENTS Number Name Date "948,143 Knox Feb. 1, 1910 "1',9'l6,-197 Baars July 4, 1933 1,994,037 Gay Mar. 12, 1935 

